Origin of uranium isotope variations in early solar nebula condensates.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 26973874.
- Also identified by DOI 10.1126/sciadv.1501400 and PMC identifier 4783122.
- Licence recorded as CC BY-NC.
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Abstract
High-temperature condensates found in meteorites display uranium isotopic variations ((235)U/(238)U), which complicate dating the solar system's formation and whose origin remains mysterious. It is possible that these variations are due to the decay of the short-lived radionuclide (247)Cm (t 1/2 = 15.6 My) into (235)U, but they could also be due to uranium kinetic isotopic fractionation during condensation. We report uranium isotope measurements of meteoritic refractory inclusions that reveal excesses of (235)U reaching ~+6% relative to average solar system composition, which can only be due to the decay of (247)Cm. This allows us to constrain the (247)Cm/(235)U ratio at solar system formation to (1.1 ± 0.3) × 10(-4). This value provides new clues on the universality of the nucleosynthetic r-process of rapid neutron capture.
Medical subject headings
- Solar System
- Uranium